﻿using System;
using System.IO;

namespace ReplaceSubstring
{
    class ReplaceSubstring
    {
        static void Main()
        {
            string input = "..\\..\\File.txt",
                result = "..\\..\\Result.txt",
                line;

            using (StreamReader reader = new StreamReader(input))
            {
                using (StreamWriter writer = new StreamWriter(result))
                {
                    while ((line = reader.ReadLine()) != null)
                    {
                        writer.WriteLine(line.Replace("start", "finish"));
                    }
                }
            }
        }
    }
}
